Agri-forest-wetland combined ecological space integrated woodland and wetland around agricultural land. It played the role of water purification and biological habitat effect and better restored the endogenous circulation of water and fertilizer in rural ecological space. Taking Shanghai Agriculture, Forestry and Water Town as an example, using the ecological space composite design concept, transforming the understory space around farmland, introducing native wet plants and native trees and shrubs, introducing biological channels, and creating wetland forests and shallow ponds for plants. The agri-forest-wetland combined ecological system was composed of pre-reservoir, cultivation area, water conservation area, water forest, forest wetland, and other units. It was a complex ecological space absorbing excess nutrients and protecting biological habitats. This combined ecological system restored the circulation of water and fertilizer and provided a systematic solution to improve the ecological quality of rural areas.